# Questions tagged [swap-test]

For questions related to the "Swap test": a quantum algorithm whose purpose is to quantify the distance between two given quantum states.

16 questions
Filter by
Sorted by
Tagged with
117 views

• 11.7k
111 views

### In the swap test, how is the final probability $P(0)$ calculated?

Does anyone know much about quantum dot product: Lets say: $$|\psi \rangle = \frac{|0\rangle_1|\overrightarrow{x_i}\rangle_2 + |1\rangle_1|\overrightarrow{x_j}\rangle_2}{\sqrt 2}$$ |\phi \rangle = \...
• 23
1 vote
63 views

### In a Swap Test why is the control qubit influenced and aren't the target qubits altered?

I am in a study group learning about quantum computing using O'Reilly - Programming Quantum Computing. I'm a developer, not a physicist. :) I feel like my question is rudimentary but I can't seem to ...
• 111
1 vote
67 views

### Implementing a SWAP-Test for samples with large numbers of features

I am trying to calculate the distance between sets of vectors. To do this I can create a SwapTest circuit (described here on page 34) and encode a feature vector with a U3 gate, then apply H and CSWAP ...
• 323
665 views

### How to implement the swap test with the help of qiskit?

It's creating a real confusion for me especially the parameterized circuit which I have to create. Can anybody please solve this for me? I want to create this circuit.
• 330
3k views

### How and why does swap test works?

I am having some trouble understanding why a SWAP test would work. I meant I read that and understood the concepts as follows: If the two input states are equal, the output register always results in ...
• 271
546 views

### Distance calculation between two vectors

In Quantum Machine Learning for data scientists, Page 34 gives an algorithm to calculate the distance between two classifical vectors. As mentioned in this question, it is not clear how the SwapTest ...
• 789
642 views

### Swap Test for vector difference - how are different sized inputs combined?

I'm working on a similar problem of that raised by Aman in Inner product of quantum states Concerning the use of Swap Test for calculating the difference of two vectors. An example of the original ...
• 354
I'm using the SWAP test circuit for implementing a qubit registers comparison From the documentation I could find I've understood it can be applied to input qubits |$\alpha\rangle$ and |\$\beta\...